QN Seminar David Goldhaber-Gordon (Stanford University): 'Making and using beams of electrons in graphene'



14:00 hrs


Lecture Room G, Lorentzweg 1, Delft


As soon as graphene was discovered, researchers began dreaming about the remarkable electron optics they might expect, including Klein tunnelling and sign change in index of refraction going from n to p type regions. But until recently these remained mostly a dream, since electronic mean free paths were well below a micron. Some clever experiments tested ballistic transport on very short length scales. But with advances in the past few years, mean free paths of tens of microns are now consistently achievable, opening up many new possibilities. I will tell about our recent progress on making narrow collimated beams, achieving mirror like reflection at edges, identifying scattering mechanisms that limit mean free path, and using ballistic motion to probe band structure of super lattices in exquisite detail.